Has anyone had negatives until…

After their missed period to finally get a positive?

From my fertile window, I should have gotten it already but nothing. Have had light pink brown spotting that lasted 2-3days. But no AF. But tests are negative or questionable in if faint or indent. But not getting any darker. I’ve made a drs appt but can’t get me until next week.

Any stories or advice would help for some hope.